Variation analysis of different types of callus induced from immature inflorescences of Miscanthus sacchariflorus

Miscanthus sacchariflorus is an excellent energy plant that originated in China, belonging to the genus Miscanthus of Gramineae. The immature inflorescences of the strongly salt-tolerant M. sacchariflorus accession collected from coastal saline-alkali soil were used as explants for callus induction in this study. To reveal the callus differentiation performance and plant regeneration ability of the different types of calli induced from immature inflorescences, the differences in callus induction, differentiation, rooting and, survival rate of seedlings were compared. A high frequency regeneration system of M. sacchariflorus was established based on this, which laid the foundation for the promotion, propagation, somatic cell screening, and genetic transformation of M. sacchariflorus germplasms. The optimum medium for callus induction was MS + 3.0 mg·L^–1 2, 4-D + 0.1 mg·L^–1 6-BA + 0.72 g·L^–1 proline. Four types of callus could be induced by using immature inflorescences as explants, namely, yellow callus, white callus, purple-red callus, and transparent watery stain callus, with induction rate of 7.01%, 61.92%, 21.02%, and 9.72%, respectively. The optimal differentiation medium was MS + 2.0 mg·L^–1 6-BA + 0.5 mg·L^–1 NAA. The yellow, white, and purple-red calli were all embryonic, with differentiation rates of 93.16%, 90.60%, and 29.91%, respectively. When 1/2 MS + 0.5 mg·L^–1 NAA was used as the rooting medium, the rooting rates of the regenerated plants derived from three types of callus tissue reached 100%. After seedling hardening-off, the regenerated plants were transplanted into pots filled with sterile vermiculite. All transplanted plants were still alive after 20 days. Here, we not only established an efficient regeneration system for M. sacchariflorus, but also clarified that all three types of calli (yellow, white, and purple-red), can be used for establishment of regeneration systems. However, the white callus was more easily obtained, and its differentiation rate was significantly higher than that of the purple-red callus, but there was no significant difference with the yellow callus. Therefore, the white callus is an ideal callus type for constructing an efficient regeneration system for M. sacchariflorus and is also the basis and prerequisite for the construction of efficient genetic transformation systems for germplasm improvement of M. sacchariflorus.